For transistor action which of the following statement are correct
(a) base emitter and collector regions should have smilar size and doping concentrations
(b) the base region must be very thin and lightly doped
(c ) the emitter junction is forward biased and collector junctions is reverse biased
(d)both the emitter junction as well as the collector junction are forward biased

Explanation

To determine which statements regarding transistor action are correct, let's analyze each option step by step:

1. **Understanding Transistor Structure**: A transistor consists of three regions: the emitter, base, and collector. In an NPN transistor, the emitter is heavily doped with electrons, the base is lightly doped and thin, and the collector is moderately doped.

2. **Analyzing Each Statement**:
- **(a) Base emitter and collector regions should have similar size and doping concentrations**: This statement is incorrect. The base region is designed to be thin and lightly doped to allow for efficient carrier movement, while the emitter is heavily doped and larger to inject carriers effectively.

- **(b) The base region must be very thin and lightly doped**: This statement is correct. The base must be thin to allow electrons to pass through without recombining with holes, and it is lightly doped to maintain a balance between electrons and holes.
...